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Wednesday, June 18, 2008

What is a System?

On the weekend my confusion about the whatabouts of life, the universe and everything else temporarily reached alarming proportions. Reason was that I tried to figure out what on Earth does it mean to 'fuck the system'? I have some familiarity with the four-letter word in this expression which leaves me to wonder what do we actually mean with 'system'?

Asking myself how I and most of my colleagues seem to use the word, I would have said the system is that what is described by a model (see also: Models and Theories). Then however I made the mistake of looking into the matter (e.g. in Bossel, "Systems and Models") which produced the rather abstract definition that a system is a set with elements that stand in some relation to each other, and generally has an environment that possibly provides input and absorbs output. A dictionary further explains:

(it's only 90 pages), which is essentially about systems and piles, and sub-systems and supersystems, life and love and reproduction, atoms and cats, self-reflective consciousness - and then manages in one full sweep to declare capitalism an outdated model, ventures for all-volunteer armies, and finishes with proclaiming a new kind of religion "celebrating [...] the sudden synthesis of the quarks and of the wide diversity of microparticles as well as of atoms and molecules throughout the expanding reaches of cosmic space". Wow. The author certainly had a vision. And if you want to get really confused, try reading this.

Either way, this didn't quite clarify what a system is either. To maybe explain why my confusion, let me ask instead: What is not a system?

Lazlo goes and piles rubbish as an example (p.25). Systems, so he argues, change qualities with the elements added. But to a pile of rubbish you can add more rubbish, and all you get is a larger pile of rubbish. It makes only a quantitave difference, he writes, it does not change the 'system' as a whole.

Now if I think in terms of mathematical definitions I can very well understand there's things that are not systems. But if I look at the real world I can't find no example for that. Everybody who is familiar with rubbish (and as a blogger I certainly am) knows that rubbish usually doesn't just orderly add up -it can develop some dynamics on its own. The pile Lazlo discusses just reminds me of the sand-pile model, a well known example for a dynamical system with self-organized criticality. So, here it goes again, we have a 'system'. The only example I can think of where one could have, in Nature, a set of somethings without any relation (interaction) between the somethings is some sort of multiverse. The analogy to Lazlo's pile of rubbish is striking.

But if everything is a 'system' then what is it good for talking about systems? Well, the usefulness of thinking in terms of systems is one of classification. One can have varios forms of systems with specific properties. Open and closed systems. Systems in equilibrium. Biological systems. Self-aware systems. Political systems. Social systems. Academic systems. Complex systems. Their elements are typically sub-systems and they are further part of super-systems, so one gets a whole hierarchy of nested systems within systems - that span all of science.

And then you go make models of these systems, find suitable variables, extract relevant parameters to try to understand the system and make predictions. Within the appropriate limits you can neglect the details of the sub-systems and talk about the system and its properties as an 'organized whole'. Might that be neglecting the quark content of molecules in a system called 'cell', or neglecting the hair color of scientists in a system called 'academia'. This procedure of neglecting finer structure and details is widely used, even within physics itself, e.g. if you think about effective theories.

I guess what confused me about this book is the author's proclamation of a paradigm shift and a change towards a "holistic vision", against reductionism, and for abandoning the "mechanistic worldview of the classical disciplines" (he seems to have a problem specifically with physics). Anyway, I think this paradigm shift just passed me by.PS: Has clarified, thanks to Andreas.

"Screwing the system" is plugging your telephone feed into a 120 V AC socket. "Screwing with the system" is inventing an internet telephone versus plain old telephone service. The President's Analyst.

Capitalism is about capital not money. Money, like gravitation, has strong field effects from conserved flow (gravitomagnetics) and open flow (gravitoelectrics). Money confiscated by taxation destroys capital. A fraction returned as subsidies rarely restores the loss (e.g., corn into ethanol at 40% overall energy deficit).

Trash is dynamic. Compost piles self-heat, landfills emit voluminous gas whose composition varies over time. Beware of philosophers moonlighting as engineers. Chemistry is a (very) sloppy abstraction of physics. If you want an aspirin you must first make a chemist. When physics makes an aspirin,

I think one essential point of this system's approach is the notion of sub-systems that need not be further reduced to constituents, that's something which doesn't make sense to think of in a 'black box' explanation. This approach via the systems goes contra the idea of explaining everything from the fundamentals, but instead is - as far as I am concerned - more about identifying the relevant ingredients of the model and finding some effective description. Best,

A non-systems explanation of, say, Bill Gates' fortune, would say, Bill Gates created a PC operating system for IBM machines; and converted IBM's then market dominance into market dominance for his own Microsoft.

A systems approach to Bill Gates' fortune would also take into account the economic and legal/regulatory environment and the role it played in building his fortune. (For instance, since IBM was under anti-trust scrutiny from the Federal Government, it decided to license a PC operating system from an outside vendor instead of creating one of its own. US copyright enforcement was crucial to Microsoft's success, etc.)

The non-systems approach e.g, might support the myth of Bill Gates as a self-made man. In the systems approach, the confluence of factors that led to the rise of Microsoft, etc. are addressed.

Perhaps not the best of examples, and perhaps not even an accurate representation of "systems approach".

* Rather than trying to improve the braking system on a car by looking in great detail at the material composition of the brake pads (reductionist), the boundary of the braking system may be extended to include the interactions between the:

Bee: The only example I can think of where one could have, in Nature, a set of somethings without any relation (interaction) between the somethings is some sort of multiverse.

What about the "system" of primary and secondary properties? For example, what is the relation/interaction between a specific wavelength of light, and the color we perceive? Or, between a specific brain state and the color we perceive?

Obviously the above is a philosophical conjecture, but is it possible that a natural system containing an epiphenomenal element or elements (quale, in this example) might include sets of "things" that do not necessarily relate/interact with the others?

Throwing philosophy (and dualism!) aside for a moment, could there be a physically realizable parallel to the above epiphenomenal elements, such as the complex products of emergent systems?

Well, the point that I tried to make is that you can have some sort of set without any relation but this will only be an approximation. That might be an arbitrary good approximation, but it's always a matter of the range of parameters the model is good in. E.g. you could say that processes in your brain are in no relation to the star's constellation. But in fact there is some interaction between both, since in principle the star's gravitational fields extends through all of space. This is of course completely negligible for what your brain does, but it's a matter of finding out what is negligible and what isn't, finding out what are suitable sorts of systems and subsystems and in which limits which model can be applied (if you'd try to apply this model e.g. in the early universe the whole notion of a brain wouldn't make sense). I am not quite sure though this addresses your question. I don't see what, in the examples you bring up, would be the set without relations. Best,

You Said:"And then you go make models of these systems, find suitable variables, extract relevant parameters to try to understand the system and make predictions."

Simply as J.S. Bell would have reminded that the word ‘system’ is one of several words that should never be used in terms of a serious discussion:

“Why not look it up in a good book? But which good book? ……………………..From the good books known to me are not so concerned with physical precision. This is clearly from their vocabulary.

Here are some words which, however legitimate and necessary in application, have no place in a formulation with any pretension to physical precision: system, apparatus, environment, microscopic, macroscopic, reversible, irreversible, observable, information, measurement.

The concepts ‘system’, ‘apparatus’, ‘environment’, immediately imply an artificial division of the world, and an intention to neglect, or take a schematic account of the interactions across the split. The notions of ‘microscopic’ and ‘macroscopic’ defy precise definition. So also do the notions of ‘reversible’ and ‘irreversible’. Einstein said that it is theory which decides what is ‘observable’. I think he was right-‘observation’ is a complicated and theory-laden business. Then that notion should not appear in the formulation of fundamental theory. Information? Whose information? Information about what?

On this list of bad words from good books, the worst of all is ‘measurement’. It must have a section to itself.”

Surely the semantic bit that you have to consider, my dear lost soul, to isolate a system is that when you're under one you have no freedom of choice, were you an elementary particle, a proteine in a chain of chemical reactions, an insect in its colony or a true believer in some sect. What's not a system? Man is not a system (even most animals aren't)or are you a fatalist?

Hi Bee, I think the expression in Ireland and the UK is 'to buck the system', rehter more polite! It has the connotation of achieving an outcome not quite intended by those who constructed the original system(Example: Irish farmers squeezing subsidies out of the EU under all sorts of pretexts)

I still don’t understand what the blogosphere is and what the purpose of discussions initiated by your posts is (to avoid misinterpretations I consider them and the comments very interesting and enjoy reading). However, you consistently DO NOT refer to the mainstream achievements of the theoretical physics (foundations of physics). I think that at least the presentation of them will balance the discussion. In particular, the definitions what the physical system is, how it described in CM and QM and the definition/discussion of “an image or a model” (“The Physics of Model”) is given by E.Schrödinger “The present situation in QM” (1935), English translation in W&Z. Could you explain at least why you ignore it?In addition, in your discussions of “knowledge”, “illusion of knowledge”, etc. you ignore “ignorance” – state of pure WGN (vacuum).

The bottom line is that IMO the presentation of mainstream physics POV will contribute substantially to the general public understanding what “science” and “scientists” are in general and physics/physicist in particular. I have no doubt that even the journalists will understand and will accept that (it is apparently is unknown to them; as you know it is very dramatic story: L. Boltzmann, M. Curie, P. Ehrenfest, E. Fermi paid their life to remove “black holes” from physics; something opposite to hand waving with beer of drunk uneducated jerk claimed that fermions may be transformed to bosons).Regards, Dany.

P.S. Instead fuzzy running along the perimeter you may locate yourself stationary and quietly at the focal points (“roots”). Then take a “megaphone” and broadcast the voice of silent hard workers (Castalians) of the experimental and theoretical physics.

Bell is talking about the QM aspect of a 'system'. It is true that many of these concepts remain vague, esp. the question of what is the system and what is the environment. What I was aiming at here however wasn't QM, I was concerned with well, as I said, what do we mean with a political system, a social system, a biological system and so on, trying to figure out what 'General Systems Theory' is. Best,

I still don’t understand what the blogosphere is and what the purpose of discussions initiated by your posts is (to avoid misinterpretations I consider them and the comments very interesting and enjoy reading). However, you consistently DO NOT refer to the mainstream achievements of the theoretical physics (foundations of physics).

Well, this post just isn't about theoretical physics. I wasn't writing about systems in QM, I was trying to figure out what system theory is good for. What I had in mind indeed had nothing to do with physics whatsoever. Best,

Well, Dany, the fact that I'm a theoretical physicist doesn't mean that theoretical physics is the only thing I'm interested in and write about. I have never declared this a 'theoretical physics' blog, it just happened to be written by somebody working in this area. If you don't like that, nobody forces you to read what I write.

I'm not vexed. I was just looking for a definition of 'system' that works well with the way it is actually used, and I was wondering what people mean with 'complex systems' or 'political systems'. Sure, a system can have boundaries, I don't know what you're aiming at.

“Well, Dany, the fact that I'm a theoretical physicist doesn't mean that theoretical physics is the only thing I'm interested in and write about.”

I referred to that:

“Asking myself how I and most of my colleagues seem to use the word, I would have said the system is that what is described by a model (see also: Models and Theories).”

You didn’t refer on Schrödinger’s paper in your post Models and Theories either.I guess that most of your colleagues are theoretical physicists. If so, you and your colleagues must read, know and understand the above referred paper. IMO that paper should be mentioned/referred in any discussion of Models and Theories doesn’t a matter the specific application. Similarly, I am not able to imagine the professional biologist that don’t know E.Schrödinger paper “What is Life?”

Bee said:Well, I'd have said a human being is a system. Why does this make me a fatalist? Best,

> Well, according to my characterization of system as something that behaves without freedom of choice, if you call man a system then you're endorsing the old fatalist thinking from XVIII century in a way, because then man would operate following a system, probably within the reach of science explanatory power (even if only probabillistically).Is that so in your mind?

Yes I was aware of the context that J.S. Bell was talking about a ‘system’ in. The point being is that the word as a concept itself wherever used is a contrivance to a large degree and as such far too subjective to be taken seriously as to be an element of anything that is to form the foundations of any fundamental concept one wishes to study and understand in terms of predicting behavior. So no matter if it’s the Solar system or the political system what’s being discussed has boundaries and divisions that have no true significance if one is looking to have clarity and precision from the standpoint of theory. It could be a social theory or a physical theory the same would apply. So to imagine something like a "system theory" would be completely inconsistent.

I have explained previously elsewhere that in fact I don't believe in freedom of choice, so I am probably a fatalist then. That however doesn't follow from what I've explained here. That you can make predictions within a certain accuracy about a system doesn't mean its entire behavior is predetermined. Models typically apply only in certain limits or on certain timescales and in certain circumstances, within which one can make fairly reliable statements. This specification of where and when and for what the model applies is crucial to its usefulness. That is true for the 'system' that is the human being as well. We have by now a fairly accurate model e.g. of what a surgeon is likely to find inside the human body and on which place. You can predict fairly well that if he attempts a knee surgery he is unlikely to find a liver there. We know that humans can't see light in the far UV and if you cut them off oxygen supply they will die. Does that make human behavior predictable? I don't think so. The question whether it is in principle predictable isn't a question that really comes up in this context. I certainly wouldn't want to try to find a model for the behavior of a specific human, I think that's for all practical purposes not feasible. You can however make general models of how people will react in certain situations. That is done all the time. Just consider the question;: if we put a tax on this, what will people do and what are the consequences? Or, if there is a fire in the building, what will people do, and how do we get them out of here as fast as possible? How do we organize our institute such that the people who work here feel comfortable? Difficult question, and yes, everybody is an individual, but in most cases it is possible to make some general statements. Best,

Well, it just isn't a fundamental concept in any regard, and yes, there is an ambiguity in it. That doesn't mean it's a useless concept. You can e.g. study the question: If I have a system with properties X, Y, Z then what will happen in situation A, B, C? The next question is then of course, is this an actual description of nature and under which circumstances? But that's a question we always have to ask about any theory. The advantage of using a certain abstraction in that modeling procedure build on systems with certain specification is that it allows you to make general statements that possibly apply to various situations. At least as I understand it, it is in this sense that system's theory provides a generalized framework that can improve communication between very different fields of science. Just consider in how many different contexts complex or chaotic systems can play a role. Best,

"System": the behavior of anything at all, regarded as a whole (however arbitrarily the boundaries are defined) that is composed of more than one interacting constituent entities that by themselves are either completely different (or subsystems) or, at the most fundamental (quantum) level, don't do squat unless some interaction occurs.

In other words, an interaction between any two entities satisfies the definition. (If it "behaves" it must be a "system" of some kind, carried out by interaction between sub-constituent entities).

This indeed captures very well what I meant to express. Just that when I thought about it I came to the conclusion that the concept of a 'single constituent' does on a fundamental level not make sense. There are always virtual particle pairs and self-interactions that make even a single particle system one in which interactions are relevant. Maybe one should make that what is not a system is a set that contains only one subsystem which is itself and neither self-interaction nor interaction with the environment. E.g. if you'd attempt to describe a social system but only consider a set of one isolated person, this wouldn't be a system at all, since the person doesn't have anything to interact with and the self-interaction wouldn't be part of the social aspects. Did that make any sense? Anyway, again I come to conclude that this is not a system that 'really' exists, as it seems to me like simply defining the boundaries in a very inappropriate way (pushing the rest of the social system into the environment of an individuum doesn't seem to me like such a good model). Best,

Well here is a thought. (More related to social systems though.) How about defining a system as a group of people, let say between 2 and 5, that when they are together changes their behaviour.In this instance, the system is created only when it brings forward a change in the individuals behaviour.

That is an interesting suggestion, and one that goes into the direction of some thoughts I had, but not regarding systems generally, but already rather complex systems. See, if the behavior of that group doesn't change, I'd still call it a system. Though possibly a rather dull one. Best,

Well here is a thought. (More related to social systems though.) How about defining a system as a group of people, let say between 2 and 5, that when they are together changes their behaviour.In this instance, the system is created only when it brings forward a change in the individuals behaviour.